In a central office, a switch or other electronic equipment is connected to a main distributing frame. The function of the main distributing frame is to provide line protection, to facilitate cross-connecting and to facilitate testing. In one connector which is associated with the main distributing frame, the functions of protection and testing are provided.
Typically, an outside plant cable is routed to a connector. Each conductor pair is terminated in a manner to be connected to a plug-in type protector. The protector also is connected to contact elements mounted in a rear panel. A front panel includes a mass of contact elements aligned with those of the rear panel and in electrical engagement therewith. The contact elements of the front panel are connected through jumpers to equipment such as central office switches, for example.
Provisions also must be made in the central office for adding additional lines to a switch and/or for cutting in lines of a plurality of customers to a new switch. The prior art includes methods and devices for effecting cutover. For example, there is a connector system which is referred to as a 711 connector system. Such a system is disclosed in U.S. Pat. No. 4,099,822 which issued on Jul. 11, 1978 in the names of A. W. Carlisle and D. R. Frey. The 711 connector includes a connector module and a bridging module.
One problem with the above-described system is that each such system may be used only on a limited number of pairs of insulated metallic conductors. As a result, cutover is accomplished in twenty-five pair line segments. This has been acceptable practice in the United States. However, in Europe, what is desired is that all the lines associated with a single switch be cut over at one time. Also, use of the aforementioned 711 system requries a presser type tool which is needed to cause one portion of the connector to be assembled to another portion.
In one method of arranging a cutover to a switch, for example, the plug-in protectors are pulled out to a detent position so that the switch is disconnected from outside plant cable as the conductors thereof are connected to ones of the protectors. After jumpers which are connected to equipment are connected to the contact elements in the front panel and the incoming cables connected to terminals into which the protectors are to be plugged, a craftsperson pushes each protector into a seated position. As should be apparent, this is a very time consuming process. Ideally, all the protectors are seated in a factory and other means used in the field to connect simultaneously all the protectors to equipment such as a switch, for example.
The prior art also includes a system for effecting cutover of a very large number of customer lines at one time. Such a system includes a mass of electrically conductive clips which are often referred to as split beam or bifurcated contact elements. In the prior art connecting arrangement, a plurality of split beam type connectors are mounted in a front face panel. Each of the split beam connectors may be a trifurcated contact element such as is disclosed in U.S. Pat. No. 4,421,374 which issued on Dec. 20, 1983 in the names of L. M. Montilla, Jr. and A. Uchuck. Each trifurcated contact includes a body portion which includes two generally parallel conductor-receiving slots to form a center portion and two outer beams. Each of the outer beams may be displaced relative to the center portion to allow a portion of an insulated conductor to be moved into the slot. When a conductor is moved into a slot, edge portions which define the slot displace insulation of the conductor and engage the conductive portion of the insulated conductor. Electrical continuity is thereby established between the insulated conductor which had been moved into the slot and an opposite end of the trifurcated portion.
Aligned with an opposite end of each trifurcated contact element is a finger of a metallic contact element. The contact element is connected to a cable such that conductors of the cable are connectable through the contact element and the trifurcated contact element to jumpers which are connected to the trifurcated contact elements. Electircal contact between the two contact elements is prevented inasmuch as a leading portion of the finger is held spaced apart from the trifurcated contact element by a strip of insulation. The strip of insulation extends between a plurality of aligned sets of fingers and trifurcated contact elements. One end portion of the strip of insulation includes an opening. A plurality of the rows of the trifurcated contact elements extend from the front face panel with the openings in the end portions of the insulative strips being generally aligned. A strand material such as a cord extends through the aligned openings of the strips. When cutover is desired, a craftsperson pulls the strand outwardly thereby to remove the strips of insulation and cause the fingers to engage electrically associated ones of the trifurcated contact elements.
Although the just-described arrangement provides for effective cutover of a mass of customer lines, it does have at least one shortcoming. Once the strips of insulation material have been pulled and connections established, it would be a difficult if not economically prohibitive task to cause disconnection of the mass of lines.
What is desired is a connector system which is particularly suited for use in a central office to effect cutover simultaneously of a mass of customer lines in a manner more simply than those available in the prior art. The sought after arrangement should be one which after connection is capable of disconnection as desired. Of course, the connective arrangement should be such that the connection and disconnection of the mass of customer lines is easily carried out.